We are excited to welcome John Keller, Director of Fiske Planetarium and Teaching Professor of Distinction in the Astrophysical and Planetary Sciences Department at the University of Colorado Boulder.
Thursday, October 16th at 7pm
at 1515 Fredreicks, San Luis Obispo
Dr. Keller received his PhD in Planetary Science from the University of Arizona and previously served as a Professor of Physics at Cal Poly San Luis Obispo for ten years before moving to Boulder. His research focuses on astronomy education as well as studying the outer Solar System, particularly asteroids observed through occultations.
In this talk, Dr. Keller will highlight how stellar occultations—events where asteroids pass in front of distant stars—can be used to measure the size, shape, and evolution of Trojan asteroids. He will also introduce Science through Shadows, a NASA Science Activation project that creates short films about eclipses, occultations, and transits. Alongside his own work, Dr. Keller will share updates on the project’s coverage of the 2023 and 2024 solar eclipses and the upcoming NASA PUNCH Mission.
This promises to be a fascinating evening that blends cutting-edge planetary science with innovative science communication. Don’t miss the opportunity to learn from Dr. Keller’s unique perspective as both a researcher and planetarium director.
Background Information
The NASA PUNCH Mission (Polarimeter to Unify the Corona and Heliosphere) is a set of four suitcase-sized satellites scheduled to launch in 2025 to study the Sun’s outer atmosphere, called the corona, and how it flows outward into space as the solar wind. Together, the satellites will create a continuous wide-field view of the entire inner solar system, essentially giving us a “weather map” of solar wind and coronal structures. PUNCH will help scientists understand how the solar wind forms, how events like coronal mass ejections travel through space, and how solar activity affects Earth and other planets.
Learn more about NASA’s PUNCH Mission here.
What are Trojan Asteroids?
Trojan asteroids are small bodies that share a planet’s orbit around the Sun. Instead of colliding with the planet, they remain in stable positions called Lagrange points—gravitational “sweet spots” where the pull of the planet and the Sun balance out. For Jupiter, these points lie about 60° ahead of the planet (the L4 point) and 60° behind it (the L5 point). Thousands of Trojan asteroids have been discovered near Jupiter’s Lagrange points, orbiting the Sun in step with the giant planet.
These objects are especially interesting because they are thought to be leftovers from the early solar system, essentially fossils from the time when the planets were forming. Studying their composition, sizes, and orbits gives astronomers clues about how material moved around in the young solar system, how the giant planets migrated, and how our current planetary system took shape. Because they have been relatively undisturbed for billions of years, the Trojans preserve a record of solar system history that is difficult to find elsewhere.
Learn about Trojan Asteroids here.
Live Launch of Lucy
The Lucy mission is a NASA spacecraft launched in 2021 to study the Trojan asteroids, a group of primitive asteroids that share Jupiter’s orbit around the Sun. These bodies are thought to be leftovers from the early solar system, holding clues to how the planets formed and evolved. Over a 12-year journey, Lucy will fly by one main-belt asteroid and multiple Trojan asteroids, capturing close-up images and gathering data on their geology, composition, density, and structure. By comparing these ancient objects, scientists hope to better understand the building blocks of planets and the processes that shaped our solar system.
Learn about Lucy here.